US3852666A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for compensation of the temperature-dependency of the conductivity of a fluid with suspended particles
Assignee: Rheinmetall Air Defence AG
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Filing: 1973-05-21
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Granted: 1974-12-03
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Expires: 1993-05-21
Abstract
Abstract A method of, and apparatus for, the compensation of the temperature-dependency of the conductivity of an electrically conductive liquid during pulse amplitude measurement of particles suspended in the liquid by means of a conductivity cell, especially during the determination of the mean or average volume of blood particles, wherein the supply of the conductivity cell in the low-frequency range is undertaken by a voltage source and in the useful frequency range by a current source. The conductivity cell is connected with a constant direct-current voltage source and with at least one frequency filter.
Inventors
- 👤 H Gahwiler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:24
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/10; G01N15/1031; G01N15/12; G01N15/131; G01N15/132
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
92 words
A method for the compensation of the temperature-dependency of the conductivity of an electrically conductive liquid during pulse amplitude measurement of particles suspended in the liquid by means of a conductivity cell, especially during the determination of the average volume of blood particles, comprising the steps of supplying the conductivity cell over its liquid-temperature dependent low-frequency range by a voltage source and over its useful frequency range for pulse amplitude measurement by a current source, and using at least one frequency filter for separating the low-frequency range from the useful frequency range.
Claim 2
Independent Claim
92 words
A method for the compensation of the temperature-dependency of the conductivity of an electrically conductive liquid during pulse amplitude measurement of particles suspended in the liquid by means of a conductivity cell, especially during the determination of the average volume of blood particles, comprising the steps of supplying the conductivity cell over its liquid-temperature dependent low-frequency range by a voltage source and over its useful frequency range for pulse amplitude measurement by a current source, and using at least one frequency filter for separating the low-frequency range from the useful frequency range.
Claim 3
Independent Claim
92 words
A method for the compensation of the temperature-dependency of the conductivity of an electrically conductive liquid during pulse amplitude measurement of particles suspended in the liquid by means of a conductivity cell, especially during the determination of the average volume of blood particles, comprising the steps of supplying the conductivity cell over its liquid-temperature dependent low-frequency range by a voltage source and over its useful frequency range for pulse amplitude measurement by a current source, and using at least one frequency filter for separating the low-frequency range from the useful frequency range.
Claim 4
Independent Claim
92 words
A method for the compensation of the temperature-dependency of the conductivity of an electrically conductive liquid during pulse amplitude measurement of particles suspended in the liquid by means of a conductivity cell, especially during the determination of the average volume of blood particles, comprising the steps of supplying the conductivity cell over its liquid-temperature dependent low-frequency range by a voltage source and over its useful frequency range for pulse amplitude measurement by a current source, and using at least one frequency filter for separating the low-frequency range from the useful frequency range.
Claim 5
Dependent Claim
67 words
The apparatus as defined in claim 2, including circuit means incorporating a series connected first amplifier, low-pass filter and a current source, said direct-current voltage source supplying the conductivity cell via said first amplifier, said low-pass filter and said current source, said circuit means further including a series connected second amplifier and a high-pass filter electrically connected with the conductivity cell and serving for decoupling pulse amplitudes.
Claim 6
Dependent Claim
76 words
The apparatus as defined in claim 2, including circuit means incorporating a series connected first amplifier, low-pass filter and resistor, said direct-current voltage source supplying the conductivity cell via said first amplifier, said low-pass filter and said resistor, said circuit means further including a series connected second amplifier and high-pass filter electrically connected with the conductivity cell and serving for decoupling pulse amplitudes, said resistor possessing a high-ohmic value in contrast to the conductivity cell resistance.
Claim 7
Dependent Claim
82 words
The apparatus as defined in claim 2, wherein said frequency filter is an inductance, said inductance being dimensioned such that in the useful frequency range omega L is much greater than the resistance of the conductivity cell and for low-frequency changes omega L is much smaller than the resistance of the conductivity cell, said inductance, the constant direct-current voltage source and the conductivity cell being electrically connected in series, and output leads for pulse amplitude measurements electrically connected with the conductivity cell.
Claim 8
Dependent Claim
13 words
The apparatus as defined in claim 5, wherein the inductance comprises a coil.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |